grahamwarren: How to enter AT mode in HC-05 Bluetooth module

Things required:

1. Arduino Uno board

2. Jumper wires

3. HC-05

1. Upload a blank program to your Arduino.

2. Make the following connections:

Arduino HC-05

TX ====> TX

RX ====> RX

VCC ====> VCC

GND ====> GND

HC-05

3. Before powering up the Arduino, the little button on the HC-05 should be pressed and then released a few seconds after powering up the Arduino..

4. The HC-05 in now in AT mode and its LED will blink approximately once every 2 seconds.

5. Open serial monitor in the Arduino program. The Baud rate should be selected to 38400 and both nl and cr should be selected.

6. Check some AT commands:

Type AT and press enter

The response should be OK

AT+ROLE? and press enter

The response is 0 or 1

0- Slave

1- Master

AT+UART? and press enter

The response is Baud rate

AT+PSWD? and press enter

The response is 1234 // that is the password.

For changing the password, command is AT+PSWD="1587"

This command will set the password to 1587

Note: you need the quotation marks around the number selected.

There are other AT commands available at this link:

grahamwarren